1 files changed, 37 insertions, 0 deletions
diff --git a/devtools/client/debugger/src/selectors/isSelectedFrameVisible.js b/devtools/client/debugger/src/selectors/isSelectedFrameVisible.js
new file mode 100644
index 0000000000..f4d42ccc1d
--- /dev/null
+++ b/devtools/client/debugger/src/selectors/isSelectedFrameVisible.js
@@ -0,0 +1,37 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at <http://mozilla.org/MPL/2.0/>. */
+
+import { originalToGeneratedId } from "devtools/client/shared/source-map-loader/index";
+import { getSelectedLocation } from "./sources";
+import { getCurrentThread, getSelectedFrame } from "./pause";
+
+function getGeneratedId(source) {
+  if (source.isOriginal) {
+    return originalToGeneratedId(source.id);
+  }
+
+  return source.id;
+}
+
+/*
+ * Checks to if the selected frame's source is currently
+ * selected.
+ */
+export function isSelectedFrameVisible(state) {
+  const thread = getCurrentThread(state);
+  const selectedLocation = getSelectedLocation(state);
+  const selectedFrame = getSelectedFrame(state, thread);
+
+  if (!selectedFrame || !selectedLocation) {
+    return false;
+  }
+
+  if (selectedLocation.source.isOriginal) {
+    return selectedLocation.source.id === selectedFrame.location.source.id;
+  }
+
+  return (
+    selectedLocation.source.id === getGeneratedId(selectedFrame.location.source)
+  );
+}